/Engine/Source/Runtime/Engine/Classes/Engine/LevelStreaming.h
Try to find loaded level in memory, issue a loading request otherwise
true if the load request was issued or a package was already loaded
virtual bool RequestLevel ( [UWorld](API\Runtime\Engine\Engine\UWorld) * PersistentWorld, bool bAllowLevelLoadRequests, [EReqLevelBlock](API\Runtime\Engine\Engine\ULevelStreaming\EReqLevelBlock) BlockPolicy )